"The Clue" - ny amerikansk högtalare

[m_persson79]

It would be very interesting to listen to theese speakers.

Jacro, are they by any chance available in Denmark?

[Jacro]

It would be very interesting to listen to theese speakers.

Jacro, are they by any chance available in Denmark?

Below is my answer from the previous post with a question about exporting The Clue:
-James

KarlXII wrote:
Impressive resume there, James. Jeez.


Again, Welcome to faktiskt.se.

Any chance we will see these speakers over here?


Thank you. With old age comes long resumes'.

I'm not sure of the President's (Lars Erickson) plans for export. I know he is a big fan of all things Scandinavian, and I would expect that he would like to have a good reason to visit more often. So, eventually, he may introduce The Clue in Sweden or other parts of Europe. As you may know, he is the US importer for Supra Cables.

For now, we are very busy working to build enough for the US market and it appears that will keep us busy for awhile.

Cheers,

- James

[celef]

tack james för ett utförligt svar, jag är väldigt nyfiken på spridningstekniken i diskanten, jag likt många andra sliter hårt för att få ihop denna del i våra hembyggda högtalare, flacka delningsfilter och inte för stora element samt att försöka rikta huvudloben på sådant sätt att man minskar dips i vistelsezonen i rummet är min lösning hitills. vet du om stereophile eller soundstage kommer testa 'the clue', det vore väldigt intressant att se mätningar på dom


translate by google:

thanks james for a detailed answer, I'm very curious as to spread the technology in the treble, I like many others work hard to get together this part of our home-built speakers, flat crossover and not for major elements and to try to target the main beam in such a way as to reduces the dips in the occupied zone in the room is my solution so far. do you know about Stereophile or Soundstage will test 'the clue', it would be very interesting to see measurements on them

[patjoh]

Interesting to have you here James, good reading. Checked out your store to http://www.definitive.com/ and it looks great.

Among all the brands you sell, what is your personal favourite speakers and amplifiers? (if you are not allowed to build them yourself )

[avr7000]

Very nice to have you here!
Welcome!

Stefan

[Jacro]

tack james för ett utförligt svar, jag är väldigt nyfiken på spridningstekniken i diskanten, jag likt många andra sliter hårt för att få ihop denna del i våra hembyggda högtalare, flacka delningsfilter och inte för stora element samt att försöka rikta huvudloben på sådant sätt att man minskar dips i vistelsezonen i rummet är min lösning hitills. vet du om stereophile eller soundstage kommer testa 'the clue', det vore väldigt intressant att se mätningar på dom


translate by google:

thanks james for a detailed answer, I'm very curious as to spread the technology in the treble, I like many others work hard to get together this part of our home-built speakers, flat crossover and not for major elements and to try to target the main beam in such a way as to reduces the dips in the occupied zone in the room is my solution so far. do you know about Stereophile or Soundstage will test 'the clue', it would be very interesting to see measurements on them

Celef,

If I understand the translation properly, you are saying that you attempt to have flat response through the crossover and at the same time target the main beam (forward vertical lobe) to the location of the listener.

I'm not sure what the english translation of; "AND NOT FOR MAJOR ELEMENTS" means.

Did you mean that you try to avoid using large transducers with large center-to-center spacing? If so, I understand.

There are a number of solutions to this problem, only a very few that are effective, most approaches compromise the end result.

As you know, the vertical and horizontal power response, are both critical, but each for different reasons and each having different criteria to achieve the best sonic result.

In terms of sending the clue out for measurement, we may do so later, but right now we are not concerned so much with getting more reviews, because we are getting more orders than we can currently supply.

Our target customer is the discerning music lover who may not have the money to buy expensive loudspeakers, and may not even be very interested in the technology, but is interested in the best musical experience.

Normally, I would not be talking so much about the technical aspects of our design, as the customer that is most interested in good music reproduction isn't always interested in the technical details as much they are interested in listening.

I talked more about the technical aspects of the clue in my posts in this forum, because I know your group understands the technical concepts and likes to know more about the acoustical design elements involved (as well as good sound quality, of course!) so I answered your questions from more of a technical viewpoint.

Best regards,

- James

[paa]

James, I'll try to make an alternative translation of parts of that text, originally written by celef, where Google Translations was a bit off:

I'm very curious about the technique with the tweeter/treble dispersion, I like many others fight hard to get this thing together in our diy speakers, low order filters and not too large drivers, and trying to aim the main lobe to minimize dips in the place we dwell, is my solution so far.

[Jacro]

James, I'll try to make an alternative translation of parts of that text, originally written by celef, where Google Translations was a bit off:

I'm very curious about the technique with the tweeter/treble dispersion, I like many others fight hard to get this thing together in our diy speakers, low order filters and not too large drivers, and trying to aim the main lobe to minimize dips in the place we dwell, is my solution so far.

Yes, that is easier for me to understand. Thank you.

In general, low order filters are better if the directivity of the drivers isn't well matched at the crossover frequency.

Low order slopes tend to help make the directivity more consistent through the crossover transition frequencies, but at a cost of worse vertical lobing, so one has to steer the axis of the lobing in a manner that creates the best result.

If the directivity of the drivers is well matched, then one can use higher order slopes to minimize interference and vertical lobing, but this also requires more precision.

That is an over simplification, as there are many factors, but generally, both approaches can effective, if the variables are well understood.

Thanks again for the translation help.

- James

[Jacro]

Very nice to have you here!
Welcome!

Stefan

Stefan,

Thanks for the warm welcome.

You guys have a great forum.

- James

[celef]

translate by google

thanks for the post james! concerning the low frequency alignment and boundary gain, can you elaborate on the mutual coupling, I do not think I've read about the effect before.

and thanks for the translation paa

[Micke23]

Vilken överraskning att konstruktören plötsligt hörde av sig i tråden. Faktiskt.se har bra genomslag, det måste man säga.

[Glebster]

Audionics of Oregon:
TL-30
M33

Snell: Type One (concept and proof of concept prototypes)

Fulton (FMI) J-Modular Premiere Subwoofer and Supertweeter

Speakerlab Delta-i Hybrid

Satterberg MW2 mid-woofer for the Rogers LS3/5a

Carver Corporation:
The Carver Amazing Loudspeaker
(Planar magnetic line source/Dipole bass 12”x 4)

Carver/Toshiba Surround Sound Television Systems

JBL/Philips Projection TV Sound Systems

Dipole Surround Patent licensed to Lucasfilm/THX

Dahlquist DQ40, DQ30, DQ16, DQ6

American Technology Corp: (Now LRAD Corporation)
Hypersonic Sound (Hyper directional, Ultrasonic-to-Audio Parametric loudspeakers)

LRAD Long Range Acoustic Device (beam formed 1.5 kilometer communications)

Stratified Field; constant directivity electrostatic loudspeakers

NeoPlanar; planar magnetic transducers

The Clue

I have about 30 or 40 patents in the field of audio, mostly loudspeakers, power amplification and signal processing and continue to do consulting for many in the industry such as SJÖFN HiFI, Atlantic Technology, Magnepan and Wisdom Audio.

Respect, welcome to faktiskt.se!

[Jacro]

Audionics of Oregon:
TL-30
M33

Snell: Type One (concept and proof of concept prototypes)

Fulton (FMI) J-Modular Premiere Subwoofer and Supertweeter

Speakerlab Delta-i Hybrid

Satterberg MW2 mid-woofer for the Rogers LS3/5a

Carver Corporation:
The Carver Amazing Loudspeaker
(Planar magnetic line source/Dipole bass 12”x 4)

Carver/Toshiba Surround Sound Television Systems

JBL/Philips Projection TV Sound Systems

Dipole Surround Patent licensed to Lucasfilm/THX

Dahlquist DQ40, DQ30, DQ16, DQ6

American Technology Corp: (Now LRAD Corporation)
Hypersonic Sound (Hyper directional, Ultrasonic-to-Audio Parametric loudspeakers)

LRAD Long Range Acoustic Device (beam formed 1.5 kilometer communications)

Stratified Field; constant directivity electrostatic loudspeakers

NeoPlanar; planar magnetic transducers

The Clue

I have about 30 or 40 patents in the field of audio, mostly loudspeakers, power amplification and signal processing and continue to do consulting for many in the industry such as SJÖFN HiFI, Atlantic Technology, Magnepan and Wisdom Audio.

Respect, welcome to faktiskt.se!

Thank you Glebster, it's good to be here.
- James

[Jacro]

translate by google

thanks for the post james! concerning the low frequency alignment and boundary gain, can you elaborate on the mutual coupling, I do not think I've read about the effect before.

and thanks for the translation paa

Celef,

Mutual coupling is the effect the diaphragm of one transducer has upon another transducer diaphragm when they are closely spaced with respect to the wavelength they are radiating. There are many variables that impact the interaction, such as baffle size and nearby boundaries (front wall, sidewalls, and floor) so the information as put forth here is a simplified representation of the effect, but hopefully, useful in providing an understanding of the concept.

In general, when two transducers are approximately ½ wavelength apart, the mutual coupling starts to cause an increase in radiation resistance, which in turn causes an increased gain in output that reaches a maximum of about +3 dB at the frequency that corresponds to approximately 1/3 wavelength. This is usually considered for two drivers mounted close together in a common enclosure, but relative to the optimization of a bass alignment, we are observing the effect, in this discussion, for two separate loudspeakers and looking at the center-to-center spacing of the left loudspeaker’s woofer in relation to the right loudspeaker’s woofer. We will make the assumption, that for most program material, frequencies below 75 Hz are substantially monophonic and correlated.

As an example, two loudspeakers that are spaced apart, such that the center-to-center distance of their woofers is 2.3M, would have the effect of maximum mutual coupling gain at the frequency corresponding to 1/3 wL, which is 50 Hz (2.3 x 3 = 6.9 M = wL @ 50Hz). Gain would begin to appear at approximately ½ wL, (75Hz) and increase below that frequency until it reached maximum coupling gain at 50 Hz.
Again, if one makes the simplification of operating on an infinite plane/half-space, then one can change the spacing of the two woofers, and set the ½ wL corner frequency and 1/3 wL Maximum Gain frequency to optimize the output for a given loudspeaker and room conditions.

Keep in mind, that in the real world, actual sound rooms are not simple infinite plane/half-space environments and there are many factors that add complexity to the simplified illustration I am providing. One obvious issue is, that as one moves the loudspeakers closer together to raise the frequencies of mutual coupling gain, one is most likely also moving the them farther from the sidewalls and lowering the corner frequency of the boundary gain of the sidewall coupling.

This can be used as a method of maintaining consistent gain as one optimizes loudspeaker spacing for imaging, or it may used to shift the low frequency gain in a favorable manner for better low frequency response.

I hope this is useful.

If any of you are interested in studying subject further, here are two papers from the Journal of the Acoustical Society:

R. L. Pritchard, "Mutual Acoustic Impedance Between Radiators in an Infinite Rigid Plane",
32, 730 (1960).

S. J. Klapman, "Interaction Impedance of a System of Circular Pistons",
11, 289 (1939).

Also, if one wishes to read a more accessible (less mathematical) paper on the subject, try:
“Design Parameters of a Dual Woofer Loudspeaker System” by Edward M. Long, Journal of the Audio Engineering Society, October 1969, v.17, No. 5.

All the best,

- James

[paa]

James,
How would you comment on the horn community, with their compression drivers and horns that are designed more for low coloration and/or controlled directivity, than for maximum sensitivity and output. E.g. LeCleach, Kugelwellen, Tractix and Gedlees waveguides?
I believe there is quite a following in the US west coast and thus also Oregon for such things?
Do you see any advantages with any or all of those, compared to normal hifi-drivers for hifi and home theatre?

[Jacro]

James,
How would you comment on the horn community, with their compression drivers and horns that are designed more for low coloration and/or controlled directivity, than for maximum sensitivity and output. E.g. LeCleach, Kugelwellen, Tractix and Gedlees waveguides?
I believe there is quite a following in the US west coast and thus also Oregon for such things?
Do you see any advantages with any or all of those, compared to normal hifi-drivers for hifi and home theatre?

paa,

I believe this is some of most important work being done right now. The difference between a diffraction "horn" for maximum output, and a "waveguide" applied for the purpose of directivity control and optimized for minimal 'high order modes' is a significant distinction that has taken the high end consumer audio industry too long to recognize. Horns had developed such bad reputation relative to sound quality, that when the modern waveguide began to show promise, the audiophile community continued to reject them, associating them with the horns of the old days.

This area of development has not yet matured to reach its full potential, but as a tool for advancing the state of the art, it is one of the most promising.

LeCleach and Geddes have set good starting points in the formulations for the basic waveguide, but there are next generation architectures that are being developed to address the remaining device and systems issues. There continue to be some problems with many of the axi-symmetric devices and they need to evolve into more appropriate forms to maximize their potential, particularly in the larger devices.

With one of the key attributes of high quality loudspeaker development being that of directivity control, an effectively designed modern waveguide is one of the best tools to reach the most desirable target functions.

- James

[Nattlorden]

I've begun to wonder if it isn't just the waveguide but the entire speaker that should be machined into some bumpy blob thing to achieve desired radiation patterns...

[Naqref]

I've begun to wonder if it isn't just the waveguide but the entire speaker that should be machined into some bumpy blob thing to achieve desired radiation patterns...

Like Genelec?

[celef]

...

...

thank you for the post, i need to re-read it a few times. i have always thought about the loudspeaker as a mono-source, then interacting with the room or parts of the room, the interaction in a stereo setup is all new to me, i sure would have liked to discuss this in swedish

[paa]

LeCleach and Geddes have set good starting points in the formulations for the basic waveguide, but there are next generation architectures that are being developed to address the remaining device and systems issues. - James

Could you point to one or two from that next generation?
And would you consider the DXT lens one of those, or how would you categorize that design?
Have you tried or seen other ways to fight HOM than the foam plug that Geddes has patented?

[Nattlorden]

I've begun to wonder if it isn't just the waveguide but the entire speaker that should be machined into some bumpy blob thing to achieve desired radiation patterns...

Like Genelec?

If that would turn out to be the optimal shape, I'm more thinking about local protubations to incur beneficial difraction where needed, even if the result might look like

[Jacro]

...

...

thank you for the post, i need to re-read it a few times. i have always thought about the loudspeaker as a mono-source, then interacting with the room or parts of the room, the interaction in a stereo setup is all new to me, i sure would have liked to discuss this in swedish

Celef,

I'm sorry that I can't deliver the information in Swedish. Maybe someone in the forum can help us with translations.

I think it is important in two-channel loudspeaker design to always consider both loudspeakers to be an integrated system.

In fact, one must consider the pair of loudspeakers, the environment/room, and the listener all as an integrated, inter-dependent system. The loudspeakers are coupled locally (mutual coupling) and also coupled globally (listener and boundaries).

(In a perfect world, the program source and method of recording would be included, but not in today's discussion.)

Mono-source evaluation of a loudspeaker is certainly useful, but it is only the starting point, not a complete characterization.

There are more issues than I can cover in this post, but, as one example, even the interference and resulting frequency response ripple due to cross-talk of the two channels at the listener's head must be considered when balancing the loudspeaker 'system', and this can only be observed when both loudspeakers operating at the same time, and interaction at the listener's body, is considered.

With two-channel reproduction, there is far greater complexity of all the interactive effects, but also more possibilities to improve, not only the spatial aspects, but also the tonal effects.

Then, of course, there is another set of issues relative to loudspeaker design for more than two channels...

Cheers,

- James

[Jacro]

Welcome Jacro.

If you're able to manage it with through the translator - do make a footer which tells of your commercial involvement - it's a forum rule to have it like that.

Night Lord (Nattlorden)

Thank you for letting me know about the forum protocol.

I believe I have installed the footer information properly.

- James

[Glebster]

I believe I have installed the footer information properly.

Indeed you have!

[Laila]

Nu när vi har(ytterliggare) en bevisligen professionell
"högtalardesigner" på forumet . . . finns det verkligen
inga fler frågor att ställa till honom . . själv så diys:ar
jag inga egna högisar, men jag gissar/vet ju att flera
av medlemmarna bygger som bara attan. Om jag vore
som ni(diys:are) så skulle jag passa på innan han tröttnar
. . .(pga. ignorans)

[paa]

James, did you see my questions in this post:
http://www.faktiskt.se/modules.php?name ... 66#1111766
/paa

[Jacro]

LeCleach and Geddes have set good starting points in the formulations for the basic waveguide, but there are next generation architectures that are being developed to address the remaining device and systems issues. - James

Could you point to one or two from that next generation?
And would you consider the DXT lens one of those, or how would you categorize that design?
Have you tried or seen other ways to fight HOM than the foam plug that Geddes has patented?

Sorry for the delay in answering... I've been busy this week.

As you know, to reduce HOMs one can either;
1) Design the waveguide in a manner that minimizes the generation of high order modes,
or,
2) Apply an absorption means to reduce HOMs that are generated by the waveguide,

or both, of course.

In the first case, if a waveguide is very carefully designed to minimize high order modes then the addition of the absorption foam does not provide a significant audible improvement.

Alternatively, when designing a waveguide, if one can gain an advantage of some desirable parameter (such as improved directivity control) by allowing high order modes to increase, then adding the absorption material can make a significant sonic improvement.

This second approach can be used to improve the DXT type structure, which is very good at directivity control, but due to its directivity control being created by using diffraction steps, it can generate more high order modes than some of the other, low diffraction types, such as Oblate Spheroid, LeCleach, or Iwata types.

A good source for DIY waveguides that are designed for low HOMs (or low Bessel modes) is Auto-Tech in Poland.

http://www.autotech.pl/pdf/audio_en.pdf
http://www.diysoundgroup.com/WaveGuides.htm

I have been working on new waveguide topologies that are based on an elliptical variation of the Oblate Spheroid.

Here is a similar approach, which is a “Quasi-Super Elliptical Oblate Spheroid”.
http://www.diysoundgroup.com/images/lar ... 0-N3_1.jpg
It is also available to DIY builders.
This device has two significant advantages over the standard Geddes type axi-symmetric Oblate Spheroid. The waveguide mouth termination is asymmetrical, so it does not exhibit the problems with on-axis high frequency dips in on axis amplitude response. It also allows closer center-to-center spacing with the woofer/mid, so vertical nulls in the response can be separated farther apart and allow a larger usable vertical listening window.

This is a good improvement over the axi-symmetric approach, but doesn’t maintain and ideal Oblate Spheroid form. While it is possibly the best overall design of the current state of the art waveguides, this one is still somewhat compromised compared to an ideal for, so that it can mount flush on a flat frontal cabinet surface.

The waveguides I have been working on follow a more precise rendition of an oblate spheroid formulation converted to elliptical form, which must be shaped in a manner that doesn’t conveniently mount to a flat surface, but offers even a further reduction in modal distortions.
(It is somewhat similar in appearance to the Iwata structures).

In terms of your question about alternatives to foam as a method of reducing HOMs, I am currently exploring different materials than the standard acoustic foam insert, as per Geddes. Ideally, to reduce HOMs more than the fundamental signal output, one would want to have a angular absorption greater than axial absorption, so I am exploring new materials that can have absorption calibrated in an angle dependent manner.

Some of the first work on minimizing this type of horn/waveguide distortion by using foam was pursued by Milton Putnam in 1980, as described in his US patent 4,381,831. In this case, the absorption foam was used mainly at the mouth of the horn and on any diffractive edges within the horn.

I can speak more to this topic if there is specific interest.

Warm regards,

- James

[Jacro]

Interesting to have you here James, good reading. Checked out your store to http://www.definitive.com/ and it looks great.

Among all the brands you sell, what is your personal favourite speakers and amplifiers? (if you are not allowed to build them yourself )

Hi patjoh,

I didn't see your post until just now.

Two issues regarding your question;

First, since I am working mostly outside of Definitive Audio, focusing on research and development, I am no longer involved with many of the daily decisions, including which products are chosen to offer for sale.

Secondly, I'm sorry, but I prefer not to recommend or critique products, made by others, that are currently in production. I hope you understand.

I am more than happy to discuss classic products that are no longer being offered for sale.

Also, I am glad to discuss any design principles, psychoacoustics, acoustics, systems, or audio concepts in general and will gladly answer any design related questions anyone in the forum may wish to ask.

Best regards,

- James

[paa]

James, would you think the HOM reduction foam also works as an acoustic lens that further smothes the dispersion whithin the desired coverage angle?

[Jacro]

James, would you think the HOM reduction foam also works as an acoustic lens that further smothes the dispersion whithin the desired coverage angle?

Interesting idea.

The current goal of applying foam to a waveguide to reduce HOMs is to be able to maintain consistent absorption such that directivity is not changed from the ideal directivity of the waveguide. Correctly applied, directivity does not change when the foam is applied.

Attempting to use the foam to change directivity does add a degree of complexity that may be difficult to fully characterize. As one changes absorption rates, it must be achieved in a manner that the absorption discontinuities don't increase HOMs, simulating diffractive effects.

That said, the concept of using the foam to alter directivity while reducing HOMs may be a very good idea. The ability to provide an addition variable to control directivity in waveguides may allow one to relax the directivity capability of a waveguide in order to achieve an improvement of some other parameter (such as efficiency, or bandwidth, etc.), and then re-optimize the directivity with a variable density foam insert.

Definitely worth exploring.

- James